1. Technical Field
The invention relates to hoist apparatus and in particular to a portable hoist apparatus adapted to support a load at various elevations. More particularly, the invention relates to such a portable hoist apparatus in which friction between moving mechanical parts of the apparatus is significantly reduced resulting in a smoothly operating hoist.
2. Background Information
In many manufacturing processes, it is necessary to support equipment, materials, etc., at various elevations adjacent to production lines for use in the manufacturing process. Further, certain equipment and/or materials often must be moved between various production lines.
For example, many manufacturing processes include the step of product labeling, wherein a product or its container is labeled by a label applicator. Such label applicators must be moved between various production lines, and positioned at different heights with respect thereto for proper application of the labels.
Various hoist apparatus and mounting stands are disclosed in the known prior art which could be utilized in the above-described manner. The closest known prior art to the present invention is shown and described in U.S. Pat. No. 4,593,883. However, the known prior art does not disclose a hoist apparatus which reduces friction against movement of a load-supporting carriage on a ball screw by rotatably suspending the ball screw within a tubular post, and/or mounting a plurality of crowned rollers in a generally circular arrangement on the carriage, so that the rollers conform to the shape of the tubular post resulting in a curved contact therebetween rather than a line or point contact.
Thus, the need exists for a hoist apparatus in which friction between moving mechanical parts thereof is significantly reduced, so that a load can be smoothly and efficiently moved to and supported at various elevations.